Need guidance to deal with Mom's delusions.

Well, I assume dementia/Alzheimer's is involved here, even though you are not listing your question in that category. Delusions of this nature are common with brain diseases such as those and medications are available to help. She'll need an evaluation by her doctor and a MOCA or SLUMS test to see where she falls on the dementia spectrum right now. Then you'll know what you're dealing with, and how far along she is with the disease. The doctor can then prescribe medications to soothe her anxiety and calm down her delusions.

In the meantime, if she's truly feeling cold, that's a pretty easy fix; dressing her in layers is the key. Get her long underwear, first of all. Over the long underwear, put a down vest on her:
https://www.amazon.com/s?k=down+vest+women&crid=MIWB3SLDU6E9&sprefix=down+vest%2Caps%2C192&ref=nb_sb_ss_i_2_9

Be sure to put on a pair of down booties as well:
https://www.amazon.com/s?k=down+booties+for+women&crid=1PWLQ6TLQ4J3P&sprefix=down+booties%2Caps%2C200&ref=nb_sb_ss_i_3_12

Socks under the booties, of course, and something warm on her hands. A wool hat and scarf should help as well. Then you can put a warm throw around her to finish it all off.

She'll be sweating bullets in no time and then you can remove articles of clothing, one at a time.

Here is a link to an article on the subject: https://www.alzheimers.org.uk/get-support/daily-living/keeping-warm-dementia

Remember, a delusion to you is real to her. Also take into consideration that a calorie = a unit of heat. Is she eating sufficiently? If not, this could be a contributing factor to why she's so cold. If her body feels icy cold, her broken mind is telling her the reason is because your husband is blowing cold air on her. She could also have circulation issues that result in her feeling so cold all the time.

And finally, go to Alzheimers.org and read up on the subject of dementia & Alzheimers. YouTube videos by Teepa Snow are also very helpful in finding effective ways to communicate with her and to understand the disease yourself. Knowledge is power!

Wishing you the best of luck!

Her original delusion about the lights has stopped, this one will eventually also. However, she needs to be evaluated to determine what's causing the delusions. Is it psychosomatic? Is it dementia, and if so what's causing the dementia? Delusions are difficult to treat because the person truly believes what they experience, they're not very receptive to seeing a psychiatrist.

It doesn't appear that layering clothes will work, neither does denying that the problem exists. Try this... tell her your sorry but your husband thought she would like the cool air but apparently it's too much. He's dismantled the machine/fan and put it away.

If she believes it exists, she may believe its been removed.

This delusion will eventually fade but may be replaced by another. She needs to be evaluated. Bring it up at her next doctor's appt. Good luck.

Also, have her checked for a UTI. My mom's delusions are heighted when she has one.

Is dementia the cause for her delusions. I didn't see that listed on your profile. If that is the case, then, you know that there is no way you can convince someone that their delusion is false. They will just not believe you and continue to believe what they know to be true.

The repeating is also another symptom on dementia. Sometimes, it comes due to the person forgetting that they have already told you the story 25 times that day. To them, it's the first time. And, telling someone that they have already told you won't work or stop them from repeating, because, they forget that you told them that. So, it's a matter of just listening and pretending it's the first time you've heard it. Eventually, this stage will pass. With my LO, it lasted about a year, but ,people vary.

I would CHECK WITH HER DOCTOR about her being cold. It could be her thyroid. When you have low thyroid, it can make you freezing cold and nothing helps. Have they checked that lately? OH, I would NOT allow a person who has dementia to use an electric blanket. Their brain cells are damaged and she may not realize she is burning her skin. I'd avoid her being by an electric heater too. Her judgment may be impaired and she could touch it and burn herself.

I'd also inquire what is causing the delusions and memory loss, if it's not dementia.

Yes, I love the idea of "dismantling the machine." That will hopefully help her feel validated. And meantime making sure she has something warm on top of her head. My Mom is always cold and she swears that cold air is pouring in thru the walls. Not sure if there's any truth to that but a scarf with a "hoodie" type thing on it really helps her. The wool cap is a great idea. I think a lot of body heat escapes thru the top of the head.

Don't assume it is completely a delusion that she is cold. My fiance was also always cold; when I reported it to his doctor she increased his dosage of thyroid hormone and it really helped (People with low thyroid are almost always cold. These are the people who wear sweaters in the heat of July!).
Also do what Margaret Mcken suggested and buy the warmest cap you can find. Walmart sold some thick acrylic caps that had two layers for only $5.98 each. Buy non-slip socks or thick socks that aren't too tight around the top.
Continue using the space heater, and also turn up the AC to 73 or 74 if you possibly can. Close the doors to that room so the heat stays inside. Check the seal of the windows because cool air may be blowing through cracks, especially at night.
Bedridden patients almost always lose a lot of body mass, which means that their metabolism isn't creating much natural heat for them. They may need double layers of clothing.
She may be fixated on the temperature because she's anxious. See if her doctor thinks Ativan or another drug for anxiety might make her sleep better. Have her checked for a urinary tract infection; often older people don't feel pain from them, but they do feel anxious.
Last, and this may be the very best idea of all: Look on Amazon.com for a product called HotHands. Another brand is called Little Hotties. These are small, disposable handwarmers that can be shaken for a few seconds and they start heating up. They last for hours and hours, and if they start getting cold, you can often reactivate them by shaking them again. They have been one of the best things I've ever bought—Jim goes to sleep with them in his hands every night, and he very rarely is cold any more.

As usual, lealonnie1 gives excellent advice. One of the things that stands out is for you to remember that to her, she is not imagining things. In her final years, when her dementia was really advanced, my mother lived in a world of delusions; too many to even go into. One of the most fantastic was that they had moved her whole brick and mortar facility and all it’s occupants to Russia overnight. I never, ever tried to dissuade her of her delusions. If she became upset and anxious, I’d speak with the nurse and ask if she thought a mild sedative would help.

Its so difficult not to become annoyed and accept the way our loved ones are now.

You can’t fight a delusion. If you can’t redirect her, give her another blanket

my mother was positive the cat litter box was “ growing” birds that were attacking the cat. Eventually she moved on to another one.

The answer given to dismantling the machine is in my opinion brilliant

Nothing you can do or say she does not hear you or understand. My mom is almost 92 living me and hubby going on 30 years now! I believe she stated having dementia long ago. But it is 3 & 1/2 years now if full blown Louie Body Dementia now. Nothing I say or do makes any difference with her she now makes non verbal sounds. Instead of asking for something she will make these sounds. So I just let her be. After awhile I will ask her if she needs anything, 99% of the time is an unreasonable request like yesterday, she wanted her parents, or to go home which is in her mind in the 1930’s. So all I can do is put her in her wheelchair and put her in another room. That seems to do the trick.